Foam electrode and method of use thereof during tissue resection

ABSTRACT

Assemblies and methods are provided for resecting a portion of tissue to be removed (e.g., unhealthy tissue, such as cancerous tissue) from a portion of the tissue to be retained (e.g., healthy tissue) within a patient is provided. An electrically conductive fluid, such as saline, may be absorbed into a hydrophilic electrode. Electrical energy (e.g., radio frequency (RF) energy) is conveyed to or from the hydrophilic electrode while being moved in proximity to the tissue along a resection line, whereby tissue adjacent to the resection line is coagulated. A resection member, such as a blunt resection member or a resection electrode, which may be on the same device as the hydrophilic electrode, is used to separate the tissue along the resection line to resect the tissue portion to be removed from the tissue portion to be retained.

RELATED APPLICATION DATA

The present application claims the benefit under 35 U.S.C. §119 to U.S.provisional patent application Ser. No. 60/755,713 filed Dec. 29, 2005,which is hereby incorporated by reference.

FIELD OF INVENTION

The present inventions generally relate to tissue ablation devices andmethods, and particularly to ablation devices and methods for achievingtissue resection.

DESCRIPTION OF RELATED ART

Today, electrosurgery is one of the widely used surgical modalities fortreating tissue abnormalities. Electrosurgical devices fall into one oftwo categories, monopolar devices and bipolar devices. Generally,surgeons are trained in the use of both monopolar and bipolarelectrosurgical techniques, and essentially all operating rooms will befound equipped with the somewhat ubiquitous instrumentality forperforming electrosurgery.

Monopolar electrosurgical devices typically comprise an electrosurgicalprobe having a first or “active” electrode extending from one end. Theelectrosurgical probe is electrically coupled to an electrosurgicalgenerator, which provides a high frequency electric current. A remotecontrol switch is attached to the generator and commonly extends to afoot switch located in proximity to the operating theater. During anoperation, a second or “return” electrode, having a much larger surfacearea than the active electrode, is positioned in contact with the skinof the patient. The surgeon may then bring the active electrode in closeproximity to the tissue and activate the foot control switch, whichcauses electrical current to arc from the distal portion of the activeelectrode and flow through tissue to the larger return electrode.

For the bipolar modality, no return electrode is used. Instead, a secondelectrode is closely positioned adjacent to the first electrode, withboth electrodes being attached to an electrosurgical probe. As withmonopolar devices, the electrosurgical probe is electrically coupled toan electrosurgical generator. When this generator is activated,electrical current arcs from the end of the first electrode to the endof the second electrode, flowing through the intervening tissue. Inpractice, several electrodes may be employed, and depending on therelative size or locality of the electrodes, one or more electrodes maybe active.

Whether arranged in a monopolar or bipolar fashion, the active electrodemay be operated to either cut tissue or coagulate tissue. When used tocut tissue, the electrical arcing and corresponding current flow resultsin a highly intense, but localized heating, sufficient enough to breakintercellular bonds, resulting in tissue severance. When used tocoagulate tissue, the electrical arcing results in a low level currentthat denatures cells to a sufficient depth without breakingintercellular bonds, i.e., without cutting the tissue.

Whether tissue is cut or coagulated mainly depends on the geometry ofthe active electrode and the nature of the electrical energy deliveredto the electrode. In general, the smaller the surface area of theelectrode in proximity to the tissue, the greater the current density(i.e., the amount of current distributed over an area) of the electricalarc generated by the electrode, and thus the more intense the thermaleffect, thereby cutting the tissue. In contrast, the greater the surfacearea of the electrode in proximity to the tissue, the less the currentdensity of the electrical arc generated by the electrode, therebycoagulating the tissue. Thus, if an electrode having both a broad sideand a narrow side is used, e.g., a spatula, the narrow side of theelectrode can be placed in proximity to the tissue in order to cut it,whereas the broad side of the electrode can be placed in proximity tothe tissue in order to coagulate it. With respect to the characteristicsof the electrical energy, as the crest factor (peak voltage divided byroot mean squared (RMS)) of the electrical energy increases, theresulting electrical arc generated by the electrode tends to have atissue coagulation effect. In contrast, as the crest factor of theelectrical energy decreases, the resulting electrical arc generated bythe electrode tends to have a cutting effect. The crest factor of theelectrical energy is typically controlled by controlling the duty cycleof the electrical energy. For example, to accentuate tissue cutting, theelectrical energy may be continuously applied to increase its RMSaverage to decrease the crest factor. In contrast, to accentuate tissuecoagulation, the electrical energy may be pulsed (e.g., at a 10 percentduty cycle) to decrease its RMS average to increase the crest factor.

Notably, some electrosurgical generators are capable of beingselectively operated in so-called “cutting modes” and “coagulationmodes.” This, however, does not mean that the active electrode that isconnected to such electrosurgical generators will necessarily have atissue cutting effect if operated in the cutting mode or similarly willhave a tissue coagulation effect if operated in the coagulation mode,since the geometry of the electrode is the most significant factor indictating whether the tissue is cut or coagulated. Thus, if the narrowpart of an electrode is placed in proximity to tissue and electricalenergy is delivered to the electrode while in a coagulation mode, thetissue may still be cut.

There are many medical procedures in which tissue is cut or carved awayfor diagnostic or therapeutic reasons. For example, during hepatictransection, one or more lobes of a liver containing abnormal tissue,such as malignant tissue or fibrous tissue caused by cirrhosis, are cutaway. There exists various modalities, including mechanical, ultrasonic,and electrical (which includes RF energy), that can be used to effectresection of tissue. Whichever modality is used, extensive bleeding canoccur, which can obstruct the surgeon's view and lead to dangerous bloodloss levels, requiring transfusion of blood, which increases thecomplexity, time, and expense of the resection procedure. To preventextensive bleeding, hemostatic mechanisms, such as blood inflowocclusion, coagulants (e.g., Surgicel™ or Tisseel™), and energycoagulation (e.g., electrosurgical coagulation or argon-beamcoagulation), can be used.

In the case where an electrosurgical coagulation means is used, thebleeding can be treated or avoided by coagulating the tissue in thetreatment areas with an electro-coagulator that applies a low levelcurrent to denature cells to a sufficient depth without breakingintercellular bonds, i.e., without cutting the tissue. Because of theirnatural coagulation capability, ease of use, and ubiquity,electrosurgical modalities are often used to resect tissue.

During a typical electrosurgical resection procedure, electrical energycan be conveyed from an electrode along a resection line in the tissue.The electrode may be operated in a manner that incises the tissue alongthe resection line, or coagulates the tissue along the resection line,which can then be subsequently dissected using the same coagulationelectrode or a separate tissue dissector to gradually separate thetissue. In the case where an organ is resected, application of RF energydivides the parenchyma, thereby skeletalizing the organ, i.e., leavingvascular tissue that is typically more difficult to cut or dissectrelative to the parenchyma.

When a blood vessel is encountered, RF energy can be applied to shrinkthe collagen in the blood vessel, thereby closing the blood lumen andachieving hemostasis. The blood vessel can then be mechanicallytransected using a scalpel or scissors without fear of blood loss. Ingeneral, for smaller blood vessels less than 3 mm in diameter,hemostasis may be achieved within 10 seconds, whereas for larger bloodvessels up to 5 mm in diameter, the time required for hemostasisincreases to 15-20 seconds. During or after resection of the tissue, RFenergy can be applied to any “bleeders” (i.e., vessels from which bloodflows or oozes) to provide complete hemostasis for the resected organ.

When electrosurgically resecting tissue, care must be taken to preventthe heat generated by the electrode from charring the tissue, whichgenerates an undesirable odor, results in tissue becoming stuck on theelectrosurgical probe, and most importantly, increases tissueresistance, thereby reducing the efficiency of the procedure. Adding anelectrically conductive fluid, such as saline, to the electrosurgerysite cools the electrode and keeps the tissue temperature below thewater boiling point (100° C.), thereby avoiding smoke and reducing theamount of charring. The electrically conductive fluid can be providedthrough the probe that carries the active electrode or by anotherseparate device.

Although the application of electrically conductive fluid to theelectrosurgery site generally increases the efficiency of the RF energyapplication, energy applied to an electrode may rapidly diffuse intofluid that has accumulated and into tissue that has already beenremoved. As a result, if the fluid and removed tissue is not effectivelyaspirated from the tissue site, the electrosurgery may either beinadequately carried out, or a greater than necessary amount of energymust be applied to the electrode to perform the surgery. Increasing theenergy used during electrosurgery increases the chance that adjacenthealthy tissues may be damaged. At the same time that fluid accumulationis avoided, care must be taken to ensure that fluid is continuouslyflowed to the tissue site to ensure that tissue charring does not takeplace. For example, if flow of the fluid is momentarily stopped, e.g.,if the tube supplying the fluid is kinked or stepped on, or the port onthe fluid delivery device becomes clogged or otherwise occluded, RFenergy may continue to be conveyed from the electrode, thereby resultingin a condition where tissue charring may occur.

While electrosurgical resection of tissue reduces the amount of bloodloss, as compared to other tissue resection modalities, it stillinvolves a tedious process that includes painstakinglycutting/dissecting through the parenchyma and ligating and cuttingthough blood vessels.

There, thus, remains a need to provide a more efficient means forelectrosurgically resecting vascularized tissue, while preventing tissuecharring and maintaining hemostasis at the treatment site.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present inventions, a method ofresecting a portion of tissue to be removed (e.g., unhealthy tissue,such as cancerous tissue) from a portion of the tissue to be retained(e.g., healthy tissue) within a patient is provided. The tissue can takethe form of any tissue requiring treatment, such as an organ, e.g., aliver. The method comprises absorbing an electrically conductive fluid,such as saline, into a hydrophilic electrode. For example, theelectrically conductive fluid can be perfused into the hydrophilicelectrode under pressure, or the hydrophilic electrode can be dippedinto a source of the electrically conductive fluid. The hydrophilicelectrode may be composed of an electrically insulative material, inwhich case, the absorbed electrically conductive solution provides anelectrically conductive path through the hydrophilic electrode. Thehydrophilic electrode may absorb an amount of the electricallyconductive solution equal to at least the dry weight of the hydrophilicelectrode, but preferably, absorbs as much electrically conductivesolution as possible to maximize the electrical conductivity of thehydrophilic electrode. The method further comprises conveying electricalenergy (e.g., radio frequency (RF) energy) to or from the hydrophilicelectrode while being moved in proximity to the tissue along a resectionline, whereby tissue adjacent to the resection line is coagulated.

Although the present inventions should not necessarily be limited intheir broadest aspects, the use of an electrically insulativehydrophilic material is advantageous in that the hydrophilic electrodecannot be activated until it absorbs a sufficient amount of electricallyconductive fluid. Thus, unlike other electrosurgical systems thatutilize saline, the inactivation of the hydrophilic electrode willprevent tissue charring from occurring if the flow of saline is cutoffor is otherwise insufficient. In addition, because the absorbent natureof the hydrophilic electrode provides only the necessary amount ofelectrically conductive fluid to the tissue site by limiting theelectrically conductive fluid to the tissue-electrode interface, theelectrical energy conveyed to or from the hydrophilic electrode isfocused at the desired location, and the need for aspiratingelectrically conductive fluid, which may otherwise accumulate at thetissue site using other saline systems, is obviated.

The method further comprises separating the tissue along the resectionline to resect the tissue portion to be removed from the tissue portionto be retained. For example, tissue separation may comprise mechanicallyor electrically separating the coagulated tissue along the resectionline. Thus, it can be appreciated that, because the tissue has beencoagulated, blood or fluid loss is prevented, or at least minimizedduring the resection process. Electrical separation of the tissue may beaccomplished with the hydrophilic electrode or another electrodeseparate from the hydrophilic electrode. In the later case, thehydrophilic electrode and other electrode may be conveniently mounted ona single probe, and/or electrical energy may be conveyed to or from thehydrophilic electrode and the other electrode, wherein tissuecoagulation and tissue separation is simultaneously achieved. The tissuecoagulation may be performed prior to the tissue separation, whereby thecoagulated tissue is separated. Optionally, electrical energy may beconveyed to or from the hydrophilic electrode to seal an anatomicalvessel (e.g., a blood vessel) that traverses the resection line, and thesealed blood vessel can then be transected.

In accordance with a second aspect of the present inventions, anelectrosurgical probe is provided. The electrosurgical probe comprisesan elongated probe shaft, which may be rigid, and a tissue coagulationelectrode mounted to the distal end of the probe shaft. The coagulationelectrode is configured for absorbing an electrically conductive fluid,and has a leading surface that can be placed in contact with tissue. Theleading surface of the coagulation electrode may be straight, such thatit can be placed along a straight resection line. The coagulationelectrode may be composed of a hydrophilic material having thecharacteristics and accompanying advantages previously described above.In an optional embodiment, the electrode surgical probe may furthercomprising a fluid delivery conduit extending through the probe shaft influid communication with the coagulation electrode. In this manner,electrically conductive fluid may be readily provided to the coagulationelectrode on demand without displacing the electrosurgical probe fromthe tissue site. Alternatively, the coagulation electrode may berepeatedly dipped in a source of electrically conductive fluid.

The electrosurgical probe further comprises a tissue resection member,such as a blunt resection member and/or resection electrode, mounted tothe distal end of the probe shaft. The resection member has a leadingsurface configured for being placed along the leading surface of thecoagulation electrode. The leading surface may be configured forprotruding from the leading surface of the coagulation electrode to,e.g., enhance tissue resection. In an optional embodiment, the leadingsurface of the coagulation electrode is configured for being placed incontact with a tissue surface when the resection member is firmly placedin contact with the tissue surface. In this manner, tissue may besimultaneously coagulated and resected. In another optional embodiment,the leading surface of the resection member is configured for beingembedded within the coagulation electrode when the leading surface ofthe coagulation electrode is lightly placed in contact with the tissue,and for protruding from the leading surface of the coagulation electrodewhen the leading surface of the coagulation electrode is firmly placedin contact with the tissue. In this manner, tissue can be selectivelycoagulated and/or resected, depending on the pressure applied at theelectrode-tissue interface.

If the resection member is a resection electrode, it may be inelectrical contact with the coagulation electrode in a monopolarconfiguration. Alternatively, the electrosurgical probe may comprise anelectrical insulating member interposed between the resection electrodeand the coagulation electrode, in which case, the resection electrodeand coagulation electrode can be in a bipolar configuration. In additionto the typical advantages associated with configuring electrodes in abipolar configuration, the resection electrode cannot be activated untilthe coagulation electrode absorbs a sufficient amount of electricallyconductive fluid. In one embodiment, the electrical insulating memberhas a recess, in which case, the resection electrode may be seatedwithin the recess.

In certain embodiments, the tissue resection member may beadvantageously interposed between two coagulation electrode surfaces ortwo coagulation electrodes. For example, the coagulation electrode mayinclude first and second leading surface portions, in which case, theleading surface of the resection member may be configured for beinginterposed therebetween. As another example, the electrosurgical probemay comprise another tissue coagulation electrode mounted to the distalend of the probe shaft. Like the first coagulation electrode, the othercoagulation electrode is configured for absorbing an electricallyconductive fluid, and has a leading surface that can be placed incontact with tissue. In this case, the leading surface of the resectionmember is configured for being interposed between the leading surface ofthe coagulation electrode and the leading surface of the othercoagulation electrode.

In other embodiments, the electrosurgical probes may have additionaltissue coagulation/resection surfaces. For example, the coagulationelectrode may have another leading surface that can be placed in contactwith tissue, in which case, the electrosurgical probe may furthercomprise another resection member mounted to the distal end of the probeshaft. The other resection member has a leading surface configured forbeing placed along the other leading surface of the coagulationelectrode. As another example, the coagulation electrode has a leadingdistal surface, and the resection member and the other resection memberform a loop that extends around the such leading distal surface.

In accordance with a third aspect of the present inventions, anotherelectrosurgical probe is provided. The electrosurgical probe comprisesan elongated probe shaft, which may be rigid, and a tissue resectionmember, such as a blunt resection member and/or resection electrode,mounted to the distal end of the probe shaft, and configured for beingplaced in contact with a tissue surface at a resection line. Theelectrosurgical probe further comprises at least one tissue coagulationelectrode mounted to the distal end of the probe shaft, wherein thecoagulation electrode(s) is configured for absorbing an electricallyconductive fluid and for being placed in contact with the tissue surfaceon laterally opposite sides of the resection line. For example, a singlecoagulation electrode may have a pair of edge surface portions, in whichcase, the resection member will be interposed between the surfaceportions. Or the resection member may be interposed between a pair ofcoagulation electrodes. In either case, the coagulation electrode(s) maybe composed of a hydrophilic material having the characteristics andaccompanying advantages previously described above. As previouslydiscussed above, the electrosurgical probe may comprise a fluid deliveryconduit extending through the probe shaft in fluid communication withthe coagulation electrode(s), or the coagulation electrode(s) may bedipped in a source of electrically conductive fluid. The detailedstructure and relationship between the resection member and coagulationelectrode(s) may be the same as that described above.

In accordance with a fourth aspect of the present inventions, a methodof resecting tissue (e.g., highly vascularized tissue) using either ofthe previous two electrosurgical probes is provided. The methodcomprises absorbing the electrically conductive fluid into thecoagulation electrode(s), conveying electrical energy to or from thecoagulation electrode(s) to coagulate the tissue along a resection line,and manipulating the resection member to separate the tissue along theresection line. If the resection member is a resection electrode,electrical energy may be conveyed to or from the resection electrode toseparate the tissue along the resection line. The electrical energy maybe simultaneously conveyed to or from the coagulation electrode(s) andresection electrode, and/or may be conveyed between the coagulationelectrode(s) and the resection electrode to coagulate and separate thetissue along the resection line.

In accordance with a fifth aspect of the present inventions, stillanother electrosurgical probe is provided. The electrosurgical probecomprises an elongated probe shaft, which may be rigid, and a pair ofrigid opposing members distally extending from the probe shaft. Therigid members have respective inward facing surfaces that form a channeltherebetween. At least one, but preferably both, of the inward facingsurfaces have a taper, whereby a region of an anatomical vessel thatproximally slides within the channel is gradually closed by therespective inward facing surfaces. In one embodiment, the rigid membersmay be fixed relative to each other, since the tapered inward facingsurface of one or both of the rigid members effects the vesselcompression.

The electrosurgical probe further comprises a first vessel ligationelectrode adjacent the inward facing surface of one of the rigidmembers, wherein the first ligation electrode is configured forcontacting a first side (e.g., a top side) of the anatomical vessel atthe closed region. The electrosurgical probe further comprises a firsthydrophilic electrode laterally disposed relative to the one opposingmember, wherein the hydrophilic electrode is configured for contactingthe first side (e.g., the top side) of the anatomical vessel whendisposed within the channel. Whereas the first ligation electrodecontacts the closed region of the anatomical vessel, the firsthydrophilic electrode may contact the open region of the anatomicalvessel due to its lateral disposition relative to the one rigid member.Although the present inventions should not be so limited in theirbroadest aspects, contact between the first ligation electrode and theclosed region of the anatomical vessel allows larger anatomical vesselsto be sealed, since electrical energy need only traverse the reducedthickness of the closed region.

In an optional embodiment, the electrosurgical probe comprises a secondvessel ligation electrode adjacent the inward facing surface of anotherof the rigid members, wherein the second ligation electrode isconfigured for contacting a second side (e.g., a bottom side) oppositethe first side of the anatomical vessel. In this case, the hydrophilicelectrode may be laterally disposed relative to the other rigid memberand be configured for contacting the second side (e.g., the bottom side)of the anatomical vessel when disposed within the channel.

In another optional embodiment, the electrosurgical probe furthercomprises a second hydrophilic electrode laterally disposed relative tothe one rigid member, wherein the one rigid member is interposed betweenthe first and second hydrophilic electrodes, and wherein the hydrophilicelectrode is configured for contacting the first side of the anatomicalvessel when disposed within the channel. In one embodiment, the ligationelectrode(s) and hydrophilic electrode(s) are in a bipolar (multipolar)relationship with the previously discussed advantages. In this case,rigid members may be composed of an electrically insulative material,and may include recess(es) in which the ligation electrode(s) arerespectively seated. The electrosurgical probe may comprise a fluiddelivery conduit extending through the probe shaft in fluidcommunication with the coagulation electrode(s), or the coagulationelectrode(s) may be dipped in a source of electrically conductive fluid.

In another optional embodiment, the rigid members have respectiveoutward facing surfaces, in which case, the electrosurgical probe mayfurther comprise a first tissue resection member (e.g., a bluntresection member and/or a resection electrode) adjacent the outwardfacing surface of one of the rigid members. A second tissue resectionmember can be provided adjacent the outward facing surface of another ofthe rigid members. If the resection member(s) are resection electrodes,the resection electrode(s) and the hydrophilic electrode(s) may be abipolar (or multipolar) relationship with the previously discussedadvantages. The first ligation electrode and first resection electrodemay be conveniently formed by the same member, as well as the optionalsecond ligation electrode and second resection electrode.

In accordance with a sixth aspect of the present inventions, yet anotherelectrosurgical probe is provided. The electrosurgical probe comprisesan elongated probe shaft and a pair of rigid, electrically insulative,opposing members distally extending from the probe shaft. The rigidmembers having inward facing surfaces that act to close an anatomicalvessel in the same manner described above. The electrosurgical probefurther comprises a metallic material disposed on the inward facingsurfaces of the rigid members, a hydrophilic material disposed on theopposing lateral surfaces of each rigid member, and at least oneconnector terminal electrically coupled to the metallic material andhydrophilic material. The hydrophilic material may have the samecharacteristics as the previously described hydrophilic material withthe associated advantages. As previously discussed above, theelectrosurgical probe may comprise a fluid delivery conduit extendingthrough the probe shaft in fluid communication with the hydrophilicmaterial, or the hydrophilic material may be dipped in a source ofelectrically conductive fluid. The detailed structure and relationshipbetween the metallic material and the hydrophilic material may be thesame as that described above with respect to the ligation electrode(s)and coagulation electrode(s). The electrosurgical probe may also havetissue resection member(s) as previously described above.

In accordance with a seventh aspect of the present inventions, a methodof ligating an anatomical vessel, e.g., a blood vessel, using either ofthe previous two electrosurgical probes is provided. The methodcomprises absorbing an electrically conductive fluid into thehydrophilic electrode (or hydrophilic material), sliding the anatomicalvessel within the channel to close a region of the anatomical vesselbetween the inward facing surfaces of the rigid members, and conveyingelectrical energy between the ligation electrode (or electricallyconductive material) and the hydrophilic electrode to seal the closedregion of the anatomical vessel. An optional method comprises conveyingelectrical energy between the ligation electrode and the hydrophilicelectrode to transect the closed region of the anatomical vessel. If theelectrosurgical probe is provided with a resection member, the methodmay further comprise conveying electrical energy to or from thehydrophilic electrode to coagulate tissue along a resection line, andmanipulating the resection member to separate the tissue along theresection line and expose the anatomical vessel on the resection line.The anatomical vessel can then be closed and sealed.

In accordance with an eighth aspect of the present inventions, yetanother electrosurgical probe is provided. The electrosurgical probecomprises an elongated probe shaft, which may be rigid, and a rigid,electrically insulative, tissue dissection member distally extendingfrom the probe shaft. As examples, the dissection may have a clamp-likeprofile or a hook-like profile. The dissection member has a pair ofmember portions having opposing inward facing surfaces that form achannel therebetween, whereby an anatomical vessel can be capturedbetween the respective inward facing surfaces. Each rigid member alsohas opposing lateral surfaces.

The electrosurgical probe further comprises a hydrophilic materialdisposed on the opposing lateral surfaces of each of the rigid memberportions, and at least one connector terminal electrically coupled tothe hydrophilic material. In one embodiment, the hydrophilic materialdisposed on the opposite lateral surfaces are in a bipolar relationship.The hydrophilic material may have the same characteristics as thepreviously described hydrophilic material with the associatedadvantages. The electrosurgical probe may comprise a fluid deliveryconduit extending through the probe shaft in fluid communication withthe hydrophilic material, or the hydrophilic material may be dipped in asource of electrically conductive fluid. In an optional embodiment, theelectrosurgical probe may comprise one or more electrodes adjacent oneor more of the inward facing surfaces. In this case, the electrode(s)and hydrophilic material may be in a bipolar relationship with thepreviously discussed advantages.

In accordance with a ninth aspect of the present inventions, a method ofligating an anatomical vessel using the previously describedelectrosurgical probe is provided. The electrosurgical probe comprisesabsorbing the electrically conductive fluid into the hydrophilicmaterial, capturing the anatomical vessel between the inward facingsurfaces of the rigid member(s), and conveying electrical energy to orfrom the hydrophilic material to seal the anatomical vessel.

In accordance with a tenth aspect of the present inventions, yet anotherelectrosurgical probe is provided. The electrosurgical probe comprisesan elongated probe shaft, which may be rigid, and a rigid electricallyinsulative, member distally extending from the probe shaft. Theelectrosurgical probe further comprises a tissue coagulation electrodeextending along one of the opposing surfaces of the rigid member, and atissue cutting electrode (e.g., a wire) extending along another of theopposing surfaces of the rigid member. Although the present inventionsshould not be so limited, this configuration allows tissue coagulationand tissue cutting to be selectively effected with one electrosurgicalprobe. The coagulation electrode may optionally be composed of ahydrophilic material having the characteristics and accompanyingadvantages previously described above. As previously discussed above,the electrosurgical probe may comprise a fluid delivery conduitextending through the probe shaft in fluid communication with thecoagulation electrode(s), or the coagulation electrode(s) may be dippedin a source of electrically conductive fluid. In one embodiment, therigid member is straight, so that the cutting electrode and coagulationelectrode are likewise straight and can therefore be placed along astraight resection line. The coagulation electrode and the cuttingelectrode may either be in a monopolar relationship or in a bipolarrelationship. In the latter case, the coagulation electrode isconfigured to contact a tissue surface when the cutting electrode isfirmly placed in contact with the tissue surface.

In accordance with an eleventh aspect of the present inventions, amethod of resecting tissue, e.g., high vascularized tissue, using thepreviously described electrosurgical probe is provided. The methodcomprises conveying electrical energy to or from the coagulationelectrode to coagulate the tissue along a resection line, and conveyingelectrical energy to or from the cutting electrode to cut the tissuealong the resection line. In one method, the cutting electrode cuts thetissue while the coagulation electrode coagulates the cut tissue. Inanother method, the coagulation electrode coagulates the tissue, andthen the cutting electrode cuts the coagulated tissue. In the case of abipolar arrangement, the electrical energy can be conveyed between thecutting electrode and the coagulation electrode to cut the tissue.

In accordance with a twelfth aspect of the present inventions, yetanother electrosurgical probe is provided. The electrosurgical probecomprises an elongated probe shaft, which may be rigid, a tapered tissueresection tip disposed at the distal end of the probe shaft, and atissue coagulation electrode mounted to the distal end of the probeshaft axially proximal to the tissue resection tip. The coagulationelectrode is configured for absorbing an electrically conductive fluid.The coagulation electrode may optionally be composed of a hydrophilicmaterial having the characteristics and accompanying advantagespreviously described above. As previously discussed above, theelectrosurgical probe may comprise a fluid delivery conduit extendingthrough the probe shaft in fluid communication with the coagulationelectrode(s), or the coagulation electrode(s) may be dipped in a sourceof electrically conductive fluid. The resection tip may be, e.g., ablunt resection tip or a resection electrode tip. In the later case, theelectrode tip may be in electrical contact with the coagulationelectrode in a monopolar configuration. Alternatively, an electricalinsulating member may be interposed between the electrode tip and thecoagulation electrode, in which case the electrode tip and coagulationelectrode may be in a bipolar configuration. Although the presentinventions should not be so limited in their broadest aspects, the axialrelationship between the resection tip and the coagulation electrodeallows tissue coagulation and resection to be accomplished during asingle movement of the electrosurgical probe along a resection line.

In accordance with a thirteenth aspect of the present inventions, amethod of resecting tissue, e.g., highly vascularized tissue, using thepreviously described electrosurgical probe is provided. The methodcomprises absorbing an electrically conductive fluid into thecoagulation electrode, conveying electrical energy to or from thecoagulation electrode to coagulate the tissue along the resection line,and manipulating the resection tip to separate the tissue along theresection line. In the case where the resection tip is an electrode tip,electrical energy can be conveyed to or from the electrode tip toseparate the tissue along the resection line. In an optional method, theelectrical energy can be simultaneously conveyed to or from thecoagulation electrode and the resection electrode tip, and in the caseof a bipolar arrangement, can be conveyed between the coagulationelectrode and the resection electrode tip to coagulate and separate thetissue along the resection line.

Other and further aspects and features of the invention will be evidentfrom reading the following detailed description of the preferredembodiments, which are intended to illustrate, not limit, the presentinventions.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the design and utility of preferred embodimentsof the present invention, in which similar elements are referred to bycommon reference numerals. In order to better appreciate how theabove-recited and other advantages and objects of the present inventionsare obtained, a more particular description of the present inventionsbriefly described above will be rendered by reference to specificembodiments thereof, which are illustrated in the accompanying drawings.Understanding that these drawings depict only typical embodiments of theinvention and are not therefore to be considered limiting of its scope,the invention will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 is a plan view of a tissue coagulation/resection systemconstructed in accordance with one preferred embodiment of the presentinvention;

FIG. 2A is a perspective view of tissue having an unhealthy tissueportion to be resected from a healthy tissue portion, wherein tissuealong a resection line has been coagulated using the tissuecoagulation/resection system of FIG. 1;

FIG. 2B is a perspective view of the tissue of FIG. 2A, wherein tissuealong the resection line has been separated using the tissuecoagulation/resection system of FIG. 1;

FIG. 2C is a perspective view of the tissue of FIG. 2A, whereinanatomical vessels have been exposed along the resection line by thetissue coagulation/resection system of FIG. 1;

FIG. 2D is a perspective of the tissue of FIG. 2A, wherein the unhealthytissue portion has been completely resected from the healthy portionusing the tissue coagulation/resection system of FIG. 1;

FIG. 3 is a perspective view of one embodiment of a tissuecoagulation/resection assembly that can disposed on the probe used inthe tissue coagulation/resection system of FIG. 1;

FIG. 4 is a perspective view of the tissue coagulation/resectionassembly of FIG. 3, particularly showing an anatomical vessel compressedand captured;

FIG. 5A is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 3, particularly showing the bipolar conveyance ofelectrical energy through the tissue;

FIG. 5B is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 3, particularly showing the tissue coagulated andseparated;

FIG. 5C is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 3, particularly showing an anatomical vessel ligated;

FIG. 6 is a cross-sectional view of another embodiment of a tissuecoagulation/resection assembly that can disposed on the probe used inthe tissue coagulation/resection system of FIG. 1, particularly showinga tissue resection electrode recessed within a tissue coagulationelectrode;

FIG. 7 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 6, particularly showing the tissue resection electrodeprotruding from the tissue coagulation electrode;

FIG. 8 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 6, particularly showing the monopolar conveyance ofelectrical energy to coagulate and separate the tissue;

FIG. 9 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 6, particularly showing the monopolar conveyance ofelectrical energy to only coagulate the tissue;

FIG. 10 is a cross-sectional view of still another embodiment of atissue coagulation/resection assembly that can disposed on the probeused in the tissue coagulation/resection system of FIG. 1;

FIG. 11 is a front view of the tissue coagulation/resection assembly ofFIG. 10;

FIG. 12 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 10, particularly showing the bipolar conveyance ofelectrical energy to coagulate and separate the tissue;

FIG. 13 is a perspective view of yet another embodiment of a tissuecoagulation/resection assembly that can disposed on the probe used inthe tissue coagulation/resection system of FIG. 1;

FIG. 14 is a perspective view of a modified tissue coagulation/resectionassembly of FIG. 13;

FIG. 15 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 13, particularly showing the monopolar conveyance ofelectrical energy to coagulate and separate the tissue;

FIG. 16 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 14, particularly showing the bipolar conveyance ofelectrical energy to coagulate and separate the tissue;

FIG. 17 is a side view of yet another embodiment of a tissuecoagulation/resection assembly that can disposed on the probe used inthe tissue coagulation/resection system of FIG. 1;

FIG. 18 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 13;

FIG. 19 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 17, particularly showing the monopolar conveyance ofelectrical energy to coagulate and separate the tissue;

FIG. 20 is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 17, particularly showing the bipolar conveyance ofelectrical energy to coagulate and separate the tissue;

FIG. 21 is a perspective view of yet another embodiment of a tissuecoagulation/resection assembly that can disposed on the probe used inthe tissue coagulation/resection system of FIG. 1;

FIG. 22 is a perspective view of the tissue coagulation/resectionassembly of FIG. 21, particularly showing an anatomical vessel captured;

FIG. 23A is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 21, particularly showing the bipolar conveyance ofelectrical energy through the tissue;

FIG. 23B is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 21, particularly showing the tissue coagulated andseparated; and

FIG. 23C is a cross-sectional view of the tissue coagulation/resectionassembly of FIG. 21, particularly showing an anatomical vessel ligated.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIG. 1 illustrates a tissue resection system 10 constructed inaccordance with a preferred embodiment of the present inventions. Thetissue resection system 10 generally comprises tissuecoagulation/resection probe 12 configured for coagulating and resectingtissue, an ablation energy source, and in particular a radio frequency(RF) generator 14, configured for supplying RF energy to the tissueresection probe 12 in a controlled manner, and an electricallyconductive fluid source, and in particular a syringe 16 configured forsupplying electrically conductive fluid (e.g., saline) to the resectionprobe 12 to provide an electrically conductive path for the RF energyfrom the resection probe 12 to the tissue to be coagulated/resected.

The coagulation/resection probe 12 generally comprises an elongatedprobe shaft 18 having a proximal end 20, a distal end 22, a handleassembly 24 mounted to the proximal shaft end 20, a tissuecoagulation/resection assembly 26 mounted to the distal shaft end 22,and a fluid conduit 28 (shown in phantom) extending through the probeshaft 18 between the proximal shaft end 20 and the probe distal end 22.In the illustrated embodiment, the probe shaft 18 is rigid, therebyproviding maximum control at the distal end 22 of the probe shaft 18.The probe shaft 18 is composed of a suitable material, such as plastic,metal or the like, and has a suitable length, typically in the rangefrom 5 cm to 30 cm, preferably from 10 cm to 20 cm. If composed of anelectrically conductive material, the probe shaft 18 is preferablycovered with an insulative material (not shown). The probe shaft 18 hasan outside diameter consistent with its intended use.

The tissue coagulation/resection assembly 26 comprises a tissuecoagulation electrode and a tissue resection member, both of which canhave a variety of structures and forms, as shown in the specificembodiments described below The coagulation electrode may be used tocoagulate tissue along a resection line, and the tissue resection membermay be used to separate the tissue along the resection line. In certainembodiments, the tissue coagulation/resection assembly 26 may be used toseal and/or transect anatomical vessels, such as blood vessels, thathave been exposed along the resection line.

The coagulation electrode has one or more leading surfaces that areconfigured for contacting tissue, and is hydrophilic in that it isconfigured for absorbing an electrically conductive fluid, such assaline. In the illustrated embodiment, the leading surfaces are straightor rectilinear, so that they can be placed along a resection line. It ispreferred that the material used in the coagulation electrode be capableof absorbing an amount of liquid at least equal to its dry weight,preferably an amount at least equal to at least two times its dryweight, and more preferably an amount at least equal to at least fourtimes its dry weight. In general, the more liquid absorbed per unitweight of the coagulation electrode, the more electrically conductivethe electrode.

Suitable materials that can be used to construct the coagulationelectrode include open-cell foam (such as polyethylene foam,polyurethane foam, polyvinylchloride foam) and medical-grade sponges. Inthe illustrated embodiment, a foam composed of Hypol 3000 base polymermarketed by W.R. Grace & Co, an L-62 Surfactant marketed by BASFCorporation, and water is used. It has been found that the open-cellpolyurethane foam marketed by Avitar, Inc. as Hydrosorb™ is especiallysuitable, and is capable of absorbing an amount of liquid twenty timesits dry weight. Polyvinyl acetal sponges, such as Merocel™, marketed byMedtronic, Inc., and cellulose sponges, such as Weckcel™ are alsosuitable. It should be appreciated that material, other than foam orsponges, may be used for the coagulation electrode as long as it iscapable of absorbing a sufficient amount of liquid. For example,spun-laced polyester, cotton, gauze, cellulose fiber, or the like can beused.

It can be appreciated that, although suitable materials used in thecoagulation electrode will typically be electrically insulative, theelectrode will become electrically conductive upon absorption ofelectrically conductive fluid. This is advantageous because thecoagulation electrode cannot be activated until it absorbs a sufficientamount of electrically conductive fluid. Thus, unlike otherelectrosurgical systems that utilize saline, the inactivation of theelectrode will prevent tissue charring from occurring if the flow ofsaline is cutoff or is otherwise insufficient. In addition, because theabsorbent nature of the coagulation electrode provides only thenecessary amount of electrically conductive fluid to the tissue site bylimiting the electrically conductive fluid to the tissue-electrodeinterface, the electrical energy conveyed by the electrode is focused atthe desired location, and aspiration of electrically conductive fluid,which may otherwise accumulate at the tissue using other saline systems,is obviated.

The tissue resection member has a leading surface, which in someembodiments, may be interposed between a pair of leading surfaces of thecoagulation electrode, as will be described in further detail below. Inthe illustrated embodiment, the leading surface is straight orrectilinear, so that it can be placed along a resection line. The tissueresection member may be a blunt resection member, which means thattissue separation may be achieved by mechanically manipulating thetissue with the resection member, or a resection electrode, which meansthat tissue separation may be achieved by conveying electrical energy toor from the resection member to either cut the tissue or coagulate thetissue. If the resection member operates to coagulate the tissue, themechanical pressure applied by the resection member may naturallyseparate the tissue as it is coagulated. As will be described in furtherdetail below, electrical energy can either be conveyed from theresection electrode in a monopolar mode, or conveyed between theresection electrode and the coagulation electrode in a bipolar mode.

In the monopolar mode, RF current is delivered from the RF generator 14to the coagulation electrode, and if applicable the resection electrode,which means that current will pass from the respective electrode, whichis configured to concentrate the energy flux in order to have aninjurious effect on the surrounding tissue, and a dispersive electrode(not shown), which is located remotely from the electrode and has asufficiently large area (typically 130 cm² for an adult), so that thecurrent density is low and non-injurious to surrounding tissue. In theillustrated embodiment, the dispersive electrode may be attachedexternally to the patient, e.g., using a contact.

In a bipolar mode, the RF current is delivered between the coagulationelectrode and another electrode, such as a resection electrode, with oneof the electrodes being the “positive” electrode element and the otherof the electrodes being the “negative” electrode element. Bipolararrangements, which require the RF energy to traverse through arelatively small amount of tissue between the tightly spaced electrodes,are more efficient than monopolar arrangements, which require the RFenergy to traverse through the thickness of the patient's body. As aresult, bipolar electrode arrangements are generally more efficient thanmonopolar electrode arrangements. Additionally, bipolar arrangements aregenerally safer for the physician and patient, since there is anever-present danger that the physician and patient may become a groundin the monopolar arrangement, resulting in painful burns.

The handle assembly 24 is composed of any suitable rigid material, suchas, e.g., metal, plastic, or the like. The handle assembly 24 carries aperfusion port 30, which is in fluid communication with the fluiddelivery conduit 28, which is further in fluid communication with thecoagulation electrode. The handle assembly 24 further carries anelectrical connector 32 that is electrically coupled to the coagulationelectrode via the probe shaft 18. In this case, the core of the probeshaft 18 is composed of an electrically conductive material, such asstainless steel, and the exterior of the probe shaft 18 is coated withan electrically insulative material (not shown). Alternatively, theelectrical connector 32 may be electrically coupled to the coagulationelectrode via wires (not shown) extending through the probe shaft 18 andterminating within the coagulation electrode or in the shaft distal end22 (which will be electrically conductive in this case) on which thecoagulation electrode is directly mounted.

If the resection member is an resection electrode, the electricalconnector 32 may also be electrically coupled to the resectionelectrode, the manner of which will depend on whether the resectionelectrode is in a monopolar or bipolar configuration.

If a monopolar configuration is used, the electrical connector 32 may beelectrically coupled to the resection electrode via the probe shaft 18.If the coagulation electrode and resection electrode are simultaneouslyactivated, the probe shaft 18 may be used to conduct the electricalenergy to both the coagulation electrode and resection electrode. If thecoagulation electrode and resection electrode are designed to beserially activated, or otherwise must remain electrically isolated, theelectrical connector 32 may be coupled to one of the coagulationelectrode and resection electrode via wires (not shown) and to the otherof the coagulation electrode and resection electrode via the probe shaft18. Alternatively, the electrical connector 32 may be coupled to therespective coagulation electrode and resection electrode via separatewires.

If a bipolar configuration is used, the electrical connector 32 may beelectrically coupled to the coagulation electrode and resectionelectrode via the probe shaft 18 or wires as long as the respectiveelectrodes are electrically isolated from each other. In this case, theelectrical connector 32 is configured, such that one of the electrodescan be coupled to a positive pole of the RF generator 14, and the otherof the electrodes can be coupled to a negative pole of the RF generator14.

The RF generator 14 is electrically connected to the electricalconnector 32 on the probe 12 via a cable 34. The RF generator 14 may bea conventional RF power supply that operates at a frequency in the rangefrom 200 KHz to 9.5 MHz, with a conventional sinusoidal ornon-sinusoidal wave form. Such power supplies are available from manycommercial suppliers, such as Valleylab, Aspen, Bovie, and Ellman. Mostgeneral purpose electrosurgical power supplies, however, operate athigher voltages and powers than would normally be necessary or suitablefor tissue coagulation and/or cutting. Thus, such power supplies wouldusually be operated at the lower ends of their voltage and powercapabilities. More suitable power supplies will be capable of supplyingan ablation current at a relatively low voltage, typically below 150V(peak-to-peak), usually being from 50V to 100V. The power will usuallybe from 20 W to 200 W, usually having a sine wave form, although otherwave forms would also be acceptable. Power supplies capable of operatingwithin these ranges are available from commercial vendors, such asBoston Scientific Corporation of San Jose, Calif., who markets thesepower supplies under the trademarks RF2000 (100 W) and RF3000 (200 W).Optionally, the RF generator 14 may include means for conveying the RFenergy in a “coagulation mode” or a “cutting mode.” As previouslydescribed, operating an RF generator in a coagulation mode will tend tocreate a tissue coagulation effect, while operating an RF generator in acutting mode will tend to create a tissue cutting effect, althoughtissue coagulation or cutting will ultimately depend, to a greaterextent, on the structure of the electrode to or from which theelectrical energy is conveyed.

The syringe 16 is connected to the perfusion port 30 on the probe 12 viatubing 36. As briefly discussed above, the syringe 16 contains anelectrically conductive fluid, such as saline. The syringe 16 isconventional and is of a suitable size, e.g., 200 ml. In the illustratedembodiment, the electrically conductive fluid is 0.9% saline. Thus, itcan be appreciated the syringe 16 can be operated to convey the salinethrough the tubing 36, into the perfusion port 30, through the fluiddelivery conduit 28 extending through the inner probe shaft 18, and intocontact with the coagulation electrode. The normally electricallyinsulative material of the coagulation electrode, in turn, absorbs thesaline, thereby creating an electrical path through the insulativematerial and transforming the electrode into an electrically conductiveelement.

Having described the general structure and function of the tissueresection system 10, its operation in resecting tissue will bedescribed. The tissue may be located anywhere in the body whereresection may be beneficial. Most commonly, the tissue will contain asolid tumor within an organ of the body, such as the liver, kidney,pancreas, breast, prostrate (not accessed via the urethra), and thelike. In this case, an unhealthy tissue portion, e.g., a cancerousportion containing a tumor, e.g., a lobe of a liver, may be resectedfrom the healthy portion of the tissue. In the preferred method, accessto the tissue may be accomplished through a surgical opening tofacilitate movement of the resection probe within the patient as well asto facilitate removal of the resected tissue from the patient. However,access to the tissue may alternatively be provided through apercutaneous opening, e.g., laparoscopically, in which case, the tissueresection probe can be introduced into the patient through a cannula,and the removed tissue may be minsilated and aspirated from the patientthrough the cannula.

The operation of the tissue resection system 10 is described inresecting unhealthy portion of tissue to be removed from a patient,which has a tumor, from a healthy portion of tissue to be retainedwithin the patient. First, the RF generator 14 and associated cable 34are connected to the electrical connector 24 on the probe 12, and thesyringe 16 and associated tubing 36 are connected to the perfusion port30 on the probe 12. The syringe 16 is then operated, such that thesaline is conveyed under positive pressure, through the tubing 36, andinto the perfusion port 30. The saline travels through the fluid conduit28 within the probe shaft 18, and into contact with the coagulationelectrode, where it is absorbed. As a result, the coagulation electrodebecomes electrically conductive. Although perfusing the coagulationelectrode with electrically conductive fluid under pressure from thesyringe 16 or any suitable pumping mechanism provides a convenient meansfor making the coagulation electrode electrically conductive andmaintaining it as such, the coagulation electrode may simply berepeatedly dipped into a supply of electrically conductive fluid if suchperfusion means is not available.

Next, the resection probe 12 is manipulated, such that the coagulationelectrode is moved in proximity to the tissue along opposite lateralsides of a resection line, and RF energy is conveyed between the RFgenerator 14 and the coagulation electrode, resulting in the coagulationof the tissue adjacent a resection line, as illustrated in FIG. 2A. Inparticular, electrical energy is conveyed to or from the coagulationelectrode through the tissue along the resection line, therebycoagulating a band of tissue that straddles the resection line. Thecoagulation electrode may be placed in direct contact with the tissue,or alternatively, if the voltage is great enough, may be moved justabove the tissue, such that arcing occurs between the coagulationelectrode and tissue. In a monopolar arrangement, RF energy will beconveyed from the RF generator 14 to the coagulation electrode, whereasin a bipolar arrangement, the RF energy may be conveyed from the RFgenerator 14 to the coagulation electrode or from the coagulationelectrode to the RF generator 14, depending on whether the coagulationelectrode is coupled to the positive pole or negative pole of the RFgenerator 14.

Next, the coagulated tissue along the resection line is separated, asillustrated in FIG. 2B. In the illustrated method, the coagulated tissueis separated using the tissue resection member. Tissue separation caneither be mechanically achieved (in the case where the resection memberis a blunt resection member) and/or electrically achieved (in the casewhere the resection member is a resection electrode). In either case,separation of the coagulated tissue can be achieved by running theresection member along the resection line. In the case of mechanicalresection, physical pressure will need to be applied to the tissue bythe resection member. In the case of electrical resection, no physicalpressure (e.g., if the resection electrode is designed to cut) or verylittle physical pressure is required to be applied to the tissue by theresection member. Instead, the RF energy conveyed between the tissue andresection electrode provides most, if not all, of the tissue resectionenergy.

Separation of the tissue can be accomplished in a separate step aftertissue coagulation has been achieved, or can be achieved as tissuecoagulation is taking place. In the latter case, the resection member ismoved with the coagulation electrode along the resection line toseparate the tissue that is being coagulated by the coagulationelectrode. If the resection member is a resection electrode, RF energycan be simultaneously conveyed to or from the coagulation electrode andresection electrode either in a monopolar mode or a bipolar mode.

Although not as expeditious or efficient as if a resection member isprovided on the same probe as the coagulation electrode, in cases wherea resection member is not provided on the resection probe 12, the tissuemay be separated using a separate resection member, whether mechanicalor electrical, or may be even be separated using the coagulationelectrode itself. In the latter case, the tissue may be held undertension, such that resection naturally occurs along the resection lineas the adjacent tissue is weakened by coagulation.

During tissue coagulation and separation, there may be anatomicalvessels, such as blood vessels, that traverse the resection line, asillustrated in FIG. 2C. Notably, because blood vessels are mostlycomposed of collagen, they will typically remain intact even through thesurrounding tissue (e.g., the parenthymia of an organ) does separate,resulting in the skeletalization of the tissue. In this case, the tissueresection probe 12 may be used to seal the portion of the blood vesselthat traverses the resection line. The sealed portion of the bloodvessel can then be transected, as illustrated in FIG. 2D, using eitherthe tissue resection probe 12 or a separate device, such as scissors.The tissue coagulation and separation steps can be repeated until theunhealthy tissue portion has been completely resected from the healthytissue portion.

Having described the general structure and operation of the tissueablation system 10, specific embodiments of the tissuecoagulation/resection assembly will now be described. Referring to FIG.3, an embodiment of a tissue coagulation/resection assembly 46constructed in accordance with one embodiment of the present inventionsis described. The coagulation/resection assembly 46 generally comprisesa blunt tissue dissection member 48 suitably mounted to the distal endof the probe shaft 18 (shown in FIG. 1), and a pair of vessel ligationelectrodes 50 (only one shown), a pair of tissue resection electrodes52, and a pair of tissue coagulation electrodes 54 mounted to thedissection member 48.

The dissection member 48 can be composed of any suitable rigid material,but in the illustrated embodiment, is composed of an electricallyinsulative material, such as polyether ether ketone (PEEK),polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyamide,polyamide-imide (PAI), polybutadiene, polycarbonate (PC), orpolypropylene (PP), to maintain electrical isolation between thecoagulation electrodes 54 and the ligation and resection electrodes 50,52, as will be described in further detail below. In the illustratedembodiment, the dissection member 48 is composed of a unibody structure,although in alternative embodiments, the dissection member 48 maycomprise distinct pieces. Any suitable process, such as injectionmolding, can be used to form the dissection member 48.

The dissection member 48 has a clamp-like profile, and in particular,includes a pair of opposing rigid member portions 56 that form a channel58 therebetween where anatomical vessels, such as blood vessels, can becompressed and closed. The dissection member 48 has a pair of opposing,flat, inward facing surfaces 60, a pair of opposing, flat, lateralsurfaces 62 (only one shown), and a pair of opposing, flat, outwardfacing surfaces 64. In the illustrated embodiment, the rigid memberportions 56 need not move relative to each other to effect this clampingfunction. Instead, the rigid member portions 56 are fixed relative toeach other, and the inward facing surfaces 60 taper, so that the channel58 gradually narrows in the proximal direction. In this manner, a regionof an anatomical vessel that proximally slides within the channel 58 isgradually closed by the respective inward facing surfaces 60, asillustrated in FIG. 4. Alternatively, only the inward facing surface 60of one of the rigid member portions 56 is tapered in this manner, sothat the channel 58 gradually narrows in the proximal direction. Therigid member portions 56 also have rounded tips 66 that can be used asblunt tissue dissection members.

In the illustrated embodiment, the ligation electrodes 50 are composedof a biocompatible and electrically conductive and material, such asstainless steel, gold, platinum, or alloys thereof, and are locatedadjacent the inward facing surfaces 60 of the respective rigid memberportions 56. In the illustrated embodiment, each rigid member portion 56has a recess 68 (only one shown) formed within the respective inwardfacing surface 60. The ligation electrodes 50 are seated within therecesses 68 of the respective rigid member portions 56, so that aleading surface 70 of the ligation electrodes 50 are exposed and flushwith the respective inward facing surfaces 60 of the dissection member48. In this manner, the inward facing surfaces 70 of the ligationelectrodes 50 are configured for contacting opposite sides (i.e., topand bottom) of the closed region of the anatomical vessel disposedwithin the channel 58, as illustrated in FIG. 4. Thus, it can beappreciated that, because electrical energy need only traverse thereduced closed region of an anatomical vessel, larger anatomical vesselsmay be sealed with the ligation electrodes 50. The width of eachligation electrode 50 may be narrow to facilitate optional transectionof the anatomical vessel.

In the illustrated embodiment, each recess 60, and thus, each ligationelectrode 50, substantially extends the length of the respective rigidmember portion 56, so that the ligation electrodes 50 contact theanatomical vessel wherever located within the channel 58. While it ispreferable to have a pair of opposing ligation electrodes 50, inalternative embodiments, only one ligation electrode 50 is provided. Theligation electrodes 50 may be coupled to the electrical connector 32 viathe probe shaft 18 (shown in FIG. 1) or wires (not shown). Althoughelectrical energy may be delivered to the ligation electrodes 50 in amonopolar configuration, in the illustrated embodiment, electricalenergy is delivered between the ligation electrodes 50 and coagulationelectrodes 54 in a bipolar configuration to facilitate vessel ligation.

In the illustrated embodiment, the resection electrodes 52 are composedof a biocompatible, electrically conductive, rigid material, such asstainless steel, gold, platinum, or alloys thereof, and are locatedadjacent the outward facing surfaces 64 of the dissection member 48. Inthe illustrated embodiment, each rigid member portion 56 has a recess 72formed within the respective outward facing surface 64. Each resectionelectrode 52 is seated within the recess 72 of the respective rigidmember portion 56, so that a leading surface 74 of the resectionelectrodes 52 protrudes from the respective outward facing surfaces 64of the dissection member 48. In this manner, the resection electrodes 52are configured for embedding within the surface of tissue, therebyenhancing the tissue resecting effect. In the illustrated embodiment,each recess 72, and thus, each resection electrode 52, substantiallyextends the length of the respective rigid member portion 56. While itis preferable to have a pair of resection electrodes 52, in alternativeembodiments, only one resection electrode 52 is provided.

The resection electrodes 52 may be coupled to the electrical connector32 via the probe shaft 18 (shown in FIG. 1) or wires (not shown).Although electrical energy may be delivered to the resection electrodes52 in a monopolar configuration, in the illustrated embodiment,electrical energy is delivered between the resection electrodes 52 andcoagulation electrodes 54 in a bipolar configuration to facilitatetissue resection. The resection electrodes 52 and ligation electrodes 50may be electrically coupled together, so that electrical energy can besimultaneously delivered to or from the ligation and resectionelectrodes 50, 52. Alternatively, one or both of the resectionelectrodes 52 can be replaced with a blunt resection member thatgenerally takes the same form and shape as the illustrated resectionelectrodes 52, but are not configured to transmit or receive electricalenergy.

The coagulation electrodes 54 are composed of a hydrophilic material,which, as previously discussed, is configured for absorbing anelectrically conductive fluid, and may be composed of any one of avariety of materials, such as foam. The coagulation electrodes 54 may becoupled to the syringe 16 via the perfusion port 30 extending throughthe probe shaft 18 (shown in FIG. 1). A plurality of ports (not shown)may be provided within the lateral surfaces 62 of the dissection member48 to facilitate distribution of the electrically conductive fluidwithin the coagulation electrodes 54 via the dissection member 48. Thecoagulation electrodes 54 may be coupled to the electrical connector 32via the probe shaft 18 (shown in FIG. 1) or wires (not shown). Althoughelectrical energy may be delivered to the coagulation electrodes 54 in amonopolar configuration, in the illustrated embodiment, electricalenergy is delivered between the ligation and/or resection electrodes 50,52 and the coagulation electrodes 54 in a bipolar configuration tofacilitate vessel ligation/tissue resection.

In particular, the coagulation electrodes 54 may be configured for beingplaced within a bipolar (or multi-polar) relationship with the ligationelectrodes 50 or resection electrodes 52 to facilitate vessel ligationand tissue resection. To this end, the coagulation electrodes 54 andligation electrodes 50 are configured for being simultaneously placed incontact with an anatomical vessel, and the coagulation electrodes 54 andresection electrodes 52 are configured for being simultaneously placedin contact with tissue to be resected.

In particular, the dissection member 48 is interposed between thecoagulation electrodes 54, such that the coagulation electrodes 54 arelaterally disposed relative to the dissection member 48. The coagulationelectrodes 54 are suitably mounted, e.g., via bonding, to the lateralsurfaces 62 of the dissection member 48. In this manner, the coagulationelectrodes 54 are configured for contacting the open regions of ananatomical vessel laterally opposite the region of the anatomical vesselclosed within the channel 58, with each coagulation electrode 54 havinga pair of inward facing leading surfaces 76 configured for contactingopposite sides (i.e., top and bottom) of the anatomical vessel, asillustrated in FIG. 4. Each coagulation electrode 54 also has a pair ofoutward facing leading surfaces 78 configured for contacting a surfaceof tissue to be resected laterally opposite of each resection electrode52.

In the illustrated embodiment, the profiles of the coagulationelectrodes 54 are geometrically similar to the profile of the dissectionmember 48. The inward facing surfaces 60 of each coagulation electrode54 outwardly offset from the respective inward facing surfaces 60 of thedissection member 48 a small amount. Thus, it can be appreciated thatthe coagulation electrodes 54 will not hinder disposition of theanatomical vessel within the channel 58 of the dissection member 48,while ensuring that contact between the coagulation electrodes 54 andanatomical vessel is achieved. Alternatively, the inward facing surfaces60 of the coagulation electrodes 54 may be flush with, or even inwardlyoffset a small amount from, the inward facing surfaces 60 of thedissection member 48, as long as the coagulation electrodes 54 do nothinder disposition of the anatomical vessel within the channel 58, whilestill ensuring contact with the anatomical vessel when closed betweenthe rigid member portions 56.

The outward facing surfaces 64 of each coagulation electrode 54 areinwardly offset from the respective outward facing surfaces 64 of thedissection member 48 by a small amount, and the respective resectionelectrodes 52 protrude from the outward facing surfaces 64 of therespective coagulation electrodes 54. Contact between tissue to beresected and the coagulation electrodes 54 is achieved when theinterposed resection electrode 52 is firmly placed in contact with thetissue. That is, the outward facing surface 74 of the resectionelectrode 52 depresses the tissue to the extent that the outward facingsurfaces 64 of the coagulation electrodes 54 contact the tissue at theperiphery of the depression. Alternatively, the outward facing surfaces64 of the coagulation electrodes 54 may be flush with, or even outwardlyoffset from, the outward facing surfaces 64 of the dissection member 48as long as they can contact tissue to be resected simultaneously withthe respective resection electrode 52. In this case, because theresection electrode 52 is rigid, it can apply firm pressure to thetissue, even though the coagulation electrode 54, which is preferablycompliant, also contacts the tissue.

Although FIG. 3 illustrates one coagulation electrode 54 mounted to alateral surface of the dissection member 48, it should be appreciatedthat multiple coagulation electrodes 54 can be mounted to each lateralsurface of the dissection member 48. For example, an upper coagulationelectrode can be mounted to a lateral surface of the upper rigid memberportion 56, and a lower coagulation electrode can be mounted to alateral surface of the lower rigid member portion 56.

One method of using tissue coagulation/resection assembly 46 will now bedescribed in performing a tissue resection. The method comprisesabsorbing an electrically conductive fluid into the coagulationelectrodes 54, e.g., by perfusing the coagulation electrodes 54 with theelectrically conductive fluid via the perfusion port 30 (shown inFIG. 1) and/or dipping the coagulation electrodes 54 into theelectrically conductive fluid. The outward facing surface 74 of one ofthe resection electrodes 52 is placed in contact with the tissue on theresection line, and the outward facing surfaces 64 of the coagulationelectrodes 54 are placed in contact with the tissue on opposite lateralsides of the resection line. Electrical energy is then conveyed betweenthe coagulation electrodes 54 and resection electrodes 52 as the tissuecoagulation/resection assembly 46 is moved along the tissue resectionline. In this manner, tissue adjacent the resection line is coagulatedby the coagulation electrodes 54, while the tissue along the resectionline is separated by the resection electrode 52. In particular, asillustrated in FIG. 5A, electrical energy (shown by arrows) is conveyedfrom the respective coagulation electrodes 54, through the tissueadjacent the resection line, and to the resection electrode 52. As aresult, the electrical energy at the interface between the tissuesurface and the outward facing surfaces 64 of the coagulation electrodes54 coagulates a band of tissue along the resection line, and theelectrical energy at the interface between the tissue surface and theresection electrode 52 separates the coagulated band of tissue along theresection line, as illustrated in FIG. 5B.

Alternatively, if the coagulation electrodes 54 in a monopolarconfiguration, electrical energy can be conveyed to or from one of thecoagulation electrodes 54, while a different portion of that coagulationelectrode 54, e.g., a lateral surface of the coagulation electrode 54,is placed on opposite lateral sides of the resection line to coagulatethe adjacent tissue. One of the resection electrodes 52 can then be usedto separate the coagulated tissue along the resection line. Electricalenergy can be conveyed to or from the resection electrode 52 toelectrically resect the tissue, or the resection electrode 52 can beused as a blunt resection member to separate the tissue along theresection line.

When an anatomical vessel, such as a blood vessel, is encountered, theanatomical vessel can be slid within the channel 58 until the vessel iscompressed and closed between the inward facing surfaces 60 of thedissection member 48. Electrical energy is then conveyed between thecoagulation electrodes 54 and ligation electrodes 50 to seal the closedregion of the anatomical vessel. In particular, as illustrated in FIG.5C, electrical energy (shown by arrows) is conveyed from the respectivecoagulation electrodes 54, through the vessel tissue, and to theligation electrodes 50. As a result, the electrical energy at theinterface between the top side of the closed region of the vessel andthe upper ligation electrode 50, and the electrical energy at theinterface between the bottom side of the closed region of the vessel andthe lower ligation electrode 50 causes the top and bottom sides of theclosed vessel region to seal.

Depending on its diameter, the closed region of the anatomical vesselmay be transected by the ligation electrodes 50. For example, it isexpected that an anatomical vessel having a diameter of 3 mm or less maybe completely transected by the ligation electrodes 50, whereas ananatomical vessel having a diameter greater than 3 mm will only besealed by the ligation electrodes 50, and will then need to betransected with another device, such as scissors.

Referring to FIGS. 6 and 7, an embodiment of a tissuecoagulation/resection assembly 86 constructed in accordance with anotherembodiment of the present inventions is described. Thecoagulation/resection assembly 86 generally comprises a coagulationelectrode 88 and a tissue resection electrode 90.

The coagulation electrode 88 is composed of a hydrophilic material,which, as previously discussed, is configured for absorbing anelectrically conductive fluid, and may be composed of any one of avariety of materials, such as foam. The coagulation electrode 88 mayhave any one of a variety of shapes, but in the embodiment illustratedin FIG. 7, has a trapezoidal cross-sectional shape with an upper leadingsurface 92, opposing lateral leading surfaces 94, and a lower leadingsurface 96, any of which can be placed in contact with tissue to effecta coagulation function. The coagulation electrode 88 may be coupled tothe syringe 16 via the perfusion port 30 extending through the probeshaft 18 (shown in FIG. 1).

The tissue resection electrode 90 takes the form of a wire or rodcomposed of a biocompatible and electrically conductive and material,such as stainless steel, gold, platinum, or alloys thereof. Theresection electrode 90 has a leading surface 98 that can be placed incontact with tissue to effect a tissue resection function. The tissueresection electrode 90 is laterally rigid, i.e., has a shear strength,so that it resists bending when placed in firm contact with tissue. Thetissue resection electrode 90 is embedded within the coagulationelectrode 88. In particular, the coagulation electrode 88 has a recess100 that divides the lower surface 96 into a pair of lower surfaceportions. The tissue resection electrode 90 is suitably mounted, e.g.,via bonding, within the recess 100. The hydrophilic material used tofabricate the coagulation electrode 88 is compressible. In this manner,when the lower surface 96 of the coagulation electrode 88 is lightlyplaced in contact with tissue, the resection electrode 90 remainsreceded within the coagulation electrode 88 (FIG. 6), so that thecoagulation/resection assembly 86 solely effects a tissue coagulationfunction, whereas when the lower surface 96 of the coagulation electrode88 is firmly placed in contact with tissue, the leading surface 98 ofthe resection electrode 90 protrudes from the lower surface 96 of thecoagulation electrode 88 into contact with the tissue (FIG. 7), so thatthe coagulation/resection assembly 86 effects both tissue coagulationand tissue resection functions.

In the illustrated embodiment, the coagulation electrode 88 andresection electrode 90 are in contact with each other and are operatedin a monopolar arrangement. In this regard, one or both of thecoagulation electrode 88 and resection electrode 90 can be coupled tothe electrical connector 32 via the probe shaft 18 (shown in FIG. 1) orwires (not shown). Alternatively, the surface of the resection electrode90 that would otherwise come in contact with the coagulation electrode88 can be electrically insulated therefrom, so that the coagulationelectrode 88 and resection electrode 90 can be placed within a bipolararrangement. Alternatively, the resection electrode 90 can be replacedwith a blunt resection member that generally takes the same form andshape as the illustrated resection electrode 90, but is not configuredto transmit or receive electrical energy.

One method of using the tissue coagulation/resection assembly 86 willnow be described in performing a tissue resection. The method comprisesabsorbing an electrically conductive fluid into the coagulationelectrode 88, e.g., by perfusing the coagulation electrode 88 with theelectrically conductive fluid via the perfusion port 30 (shown inFIG. 1) and/or dipping the coagulation electrode 88 into theelectrically conductive fluid.

Once tissue resection is desired, as illustrated in FIG. 8, the lowersurface 96 of the coagulation electrode 88 can be firmly placed incontact with the tissue on opposite lateral sides of the tissueresection line (so that the resection electrode 90 protrudes from thecoagulation electrode 88 and contacts the tissue resection line), andelectrical energy is conveyed from both the coagulation electrode 88 andresection electrode 90 into the tissue as the tissuecoagulation/resection assembly 86 is moved along the resection line. Inthis manner, the tissue adjacent the resection line is coagulated by thecoagulation electrode 88, while the tissue along the resection line isseparated by the resection electrode 90. In particular, electricalenergy is conveyed from the coagulation electrode 88 through the tissuealong the resection line, thereby coagulating a band of tissue thatstraddles the resection line, and electrical energy is conveyed from theresection electrode 90 through the tissue along the resection line,thereby separating the band of coagulated tissue on the resection line.

If only tissue coagulation is to be achieved, e.g., to precoagulate thetissue along the resection line prior to resection, the lower surface 96of the coagulation electrode 88 is lightly placed in contact with thetissue (so that the resection electrode 90 remains recessed within thecoagulation electrode 88), and electrical energy is conveyed from thecoagulation electrode 88 into the tissue as the tissuecoagulation/resection assembly 86 is moved along the resection line, asillustrated in FIG. 9. Alternatively, other surfaces of the coagulationelectrode 88 can be used to coagulate the tissue. The coagulationelectrode 88, while the resection electrode 90 remains recessed, canalso be used to stop blood loss at select locations.

Referring to FIGS. 10 and 11, an embodiment of a tissuecoagulation/resection assembly 106 constructed in accordance with stillanother embodiment of the present inventions is described. Thecoagulation/resection assembly 106 generally comprises a tissuecoagulation electrode 108, a tissue resection electrode 110, and a rigidelectrical insulating member 112.

The coagulation electrode 108 is composed of a hydrophilic material,which, as previously discussed, is configured for absorbing anelectrically conductive fluid, and may be composed of any one of avariety of materials, such as foam. The coagulation electrode 108 mayhave any one of a variety of shapes, but in the embodiment illustratedin FIG. 11, has a square cross-sectional shape with an upper leadingsurface 114, opposing lateral leading surfaces 116, and a lower leadingsurface 118, any of which can be placed in contact with tissue to effecta coagulation function. As illustrated in FIG. 10, the coagulationelectrode 108 has a semi-spherical or round distal tip leading surface120 that can also be placed in contact with tissue to effect acoagulation function. The coagulation electrode 108 may be coupled tothe syringe 16 via the perfusion port 30 extending through the probeshaft 18 (shown in FIG. 1).

The tissue resection electrode 110 is composed of a biocompatible andelectrically conductive and material, such as stainless steel, gold,platinum, or alloys thereof. The resection electrode 110 has a leadingsurface 122 that can be placed in contact with tissue to effect a tissueresection function. The electrical insulating member 112 is composed ofan electrically insulative material, such as polyether ether ketone(PEEK), polytetrafluoroethylene (PTFE), polyoxymethylene (POM),polyamide, polyamide-imide (PAI), polybutadiene, polycarbonate (PC), orpolypropylene (PP). The electrical insulating member 112 is interposedbetween the resection electrode 110 and the coagulation electrode 108 toelectrically isolate the respective electrodes from each other. Inparticular, the electrical insulating member 112 is suitably mounted tothe coagulation electrode 108, e.g., via bonding. Both of the resectionelectrode 110 and electrical insulating member 112 take the form of awire or rod looped around the distal tip of the coagulation electrode108. Either or both of the resection electrode 110 and electricalinsulating member 112 is laterally rigid, i.e., has a shear strength, sothat the resection electrode 110 resists bending when placed in firmcontact with tissue.

The coagulation electrode 108 and resection electrode 110 may be coupledto the electrical connector 32 via the probe shaft 18 (shown in FIG. 1)or wires (not shown). Although electrical energy may be delivered to thecoagulation electrode 108 and resection electrode 110 in a monopolarconfiguration, in the illustrated embodiment, electrical energy isdelivered between the coagulation electrode 108 and resection electrode110 in a bipolar configuration to facilitate tissue resection.

In the bipolar configuration, the coagulation electrode 108 andresection electrode 110 are configured for being simultaneously placedin contact with tissue to be resected. In particular, either the uppersurface 114, the lower surface 118, or the distal surface 120 of thecoagulation electrode 108 are configured for contacting a surface oftissue to be resected laterally opposite the resection electrode 110.Contact between tissue to be resected and the coagulation electrode 108is achieved when the resection electrode 110 is firmly placed in contactwith the tissue. That is, the leading surface 122 of the resectionelectrode 110 depresses the tissue to the extent that the upper surface114, lower surface 118, or distal surface 120 of the coagulationelectrode 108 contact the tissue at the periphery of the depression. Toensure that the coagulation electrode 108 and resection electrode 110can simultaneously contact tissue, the depth or height of the insulatingmember 112 is small enough, such that the leading surface 122 of theresection electrode 110 is not too offset from the respective leadingsurface (upper surface 114, lower surface 118, or distal surface 120) ofthe coagulation electrode 108.

One method of using tissue coagulation/resection assembly 106 will nowbe described in performing a tissue resection. The method comprisesabsorbing an electrically conductive fluid into the coagulationelectrode 108, e.g., by perfusing the coagulation electrode 108 with theelectrically conductive fluid via the perfusion port 30 (shown inFIG. 1) and/or dipping the coagulation electrode 108 into theelectrically conductive fluid.

If tissue resection is desired, as illustrated in FIG. 12, the resectionelectrode 110 is firmly placed in contact with the tissue along theresection line, so that the upper surface 114, lower surface 118, ordistal surface 120 of the coagulation electrode 108 is placed in contactwith the tissue on opposite lateral sides of the tissue resection line,and electrical energy is conveyed between the coagulation electrode 108and resection electrode 110 into the tissue as the tissuecoagulation/resection assembly 106 is moved along the resection line. Inthis manner, tissue adjacent the resection line is coagulated by thecoagulation electrode 108, while the tissue along the resection line isseparated by the resection electrode 110. In particular, electricalenergy (shown by arrows) is conveyed from the coagulation electrode 108through the tissue along the resection line, and to the resectionelectrode 110, thereby coagulating a band of tissue that straddles theresection line, and separating the band of coagulated tissue on theresection line.

If only tissue coagulation is to be achieved, e.g., to precoagulatetissue prior to resection, one of the lateral surfaces 116 of thecoagulation electrode 108 is placed in contact with the tissue onopposite sides of the resection line, and electrical energy is conveyedfrom the coagulation electrode 108 into the tissue as the tissuecoagulation/resection assembly 106 is moved along the resection line. Inthis case, the coagulation electrode 108 may be operated in a monopolarmode. The lateral surfaces 116 of the coagulation electrode 108 can alsobe used to stop blood loss at select locations.

Referring to FIG. 13, an embodiment of a tissue coagulation/resectionassembly 126 constructed in accordance with yet another embodiment ofthe present inventions is described. The coagulation/resection assembly126 generally comprises a tissue coagulation electrode 128, a tissueresection electrode 130, and a rigid electrical insulating member 132.

The coagulation electrode 108 is composed of a hydrophilic material,which, as previously discussed, is configured for absorbing anelectrically conductive fluid, and may be composed of any one of avariety of materials, such as foam. The coagulation electrode 108 takesthe form of a rod having a rectangular cross-sectional shape with aleading surface 134 that can be placed in contact with tissue to effecta coagulation function. The coagulation electrode 108 also has lateralsurfaces 136 that can be placed in contact with cut tissue, as will bedescribed in further detail below. The coagulation electrode 108 may becoupled to the syringe 16 via the perfusion port 30 extending throughthe probe shaft 18 (shown in FIG. 1). The tissue resection electrode 130takes the form a wire composed of a biocompatible and electricallyconductive and material, such as stainless steel, gold, platinum, oralloys thereof. The resection electrode 130 has a leading surface 138that can be placed in contact with tissue to effect a tissue resectionfunction, and in particular, a tissue cutting function.

The electrical insulating member 132 is composed of a rigid,electrically insulating, material, such as polyether ether ketone(PEEK), polytetrafluoroethylene (PTFE), polyoxymethylene (POM),polyamide, polyamide-imide (PAI), polybutadiene, polycarbonate (PC), orpolypropylene (PP), and takes the form of a rod with a squarecross-section and having opposing surfaces 140 and 142. The electricalinsulating member 132 is interposed between the coagulation electrode128 and the resection electrode 130 to electrically isolate therespective electrodes from each other. In particular, the coagulationelectrode 128 and resection electrode 130 are suitably mounted to theopposing surfaces 140 and 142 of the insulating member 132, e.g., viabonding. The insulating member 132 is laterally rigid, i.e., has a shearstrength, so that the coagulation electrode 128 and resection electrode130 resist bending when placed in firm contact with tissue.

The coagulation electrode 128 and resection electrode 130 may be coupledto the electrical connector 32 via the probe shaft 18 (shown in FIG. 1)or wires (not shown). Although electrical energy may be delivered to thecoagulation electrode 128 and resection electrode 130 in a monopolarconfiguration, in the illustrated embodiment, electrical energy isdelivered between the coagulation electrode 128 and resection electrode130 in a bipolar configuration to facilitate tissue resection. In thiscase, as illustrated in FIG. 14, the coagulation electrode 128 may bemodified to be wider, such that contact between tissue to be resectedand the coagulation electrode 128 is achieved when the resectionelectrode 130 is firmly placed in contact with the tissue. That is, theleading surface 138 of the resection electrode 130 depresses the tissueto the extent that a surface 140 of the coagulation electrode 128contacts the tissue at the periphery of the depression. To ensure thatthe coagulation electrode 128 and resection electrode 130 cansimultaneously contact tissue, the depth or height of the insulatingmember 132 is small enough, such that the leading surface 134 of theresection electrode 130 is not too offset from the respective surface140 of the coagulation electrode 128.

One method of using tissue coagulation/resection assembly 126 will nowbe described in performing a tissue resection. The method comprisesabsorbing an electrically conductive fluid into the coagulationelectrode 128, e.g., by perfusing the coagulation electrode 128 with theelectrically conductive fluid via the perfusion port 30 (shown inFIG. 1) and/or dipping the coagulation electrode 128 into theelectrically conductive fluid.

Using the tissue coagulation/resection assembly 126 of FIG. 13 in amonopolar mode, the leading surface 138 of the resection electrode 130is placed in contact with the tissue on the resection line, whileelectrical energy (shown by arrows) is conveyed from the resectionelectrode 130 into the tissue as the tissue coagulation/resectionassembly 126 is moved along the resection line, thereby cutting thetissue along the resection line, as illustrated in FIG. 15. As theresection electrode 130 cuts through the tissue, it obtains a depth thatallows the lateral surfaces 136 of the coagulation electrode 128 tocontact the tissue on opposite lateral sides of the tissue resectionline, thereby coagulating the tissue that has just been cut. In thismanner, tissue coagulation and cutting can be accomplished during asingle movement of the along the resection line.

Alternatively, rather than cutting the tissue first with the resectionelectrode 130, the leading surface 134 of the coagulation electrode 128can be placed in contact with the tissue at opposing lateral sides ofthe resection line, and electrical energy conveyed from the coagulationelectrode 128 into the tissue as the tissue coagulation/resectionassembly 126 is moved along the resection line, thereby pre-coagulatingthe tissue along the resection line prior to resection. The leadingsurface 138 of the resection electrode 130 can then be placed in contactwith the coagulated tissue on the resection line, and electrical energyconveyed from the resection electrode 130 into the tissue as the tissuecoagulation/resection assembly 126 is moved along the resection line,thereby cutting the pre-coagulated tissue along the resection line.Tissue coagulation and separation can be repeated until the tissue iscompletely resected.

Using the coagulation/resection assembly 126 of FIG. 14 in a bipolarmode, tissue adjacent the resection line can be coagulated by thecoagulation electrode 128, while the tissue along the resection line isseparated by the resection electrode 130. In particular, as illustratedin FIG. 16, the leading surface 138 of the resection electrode 130 isfirmly placed in contact with the tissue on the resection line, so thatthe surface 142 of the coagulation electrode 128 is placed in contactwith the tissue on opposite sides of the resection line, and electricalenergy is conveyed between the coagulation electrode 128 and resectionelectrode 130 into the tissue as the coagulation/resection assembly 126is moved along the resection line. In this manner, tissue adjacent theresection line is coagulated by the coagulation electrode 128, while thetissue along the resection line is separated by the resection electrode130. In particular, electrical energy (shown by arrows) is conveyed fromthe coagulation electrode 128 through the tissue along the resectionline, and to the resection electrode 130, thereby coagulating a band oftissue that straddles the resection line, and separating the band ofcoagulated tissue on the resection line.

If only tissue coagulation is to be achieved, e.g., to precoagulatetissue prior to resection, the leading surface 134 of coagulationelectrode 128 is placed in contact with the tissue on opposite lateralsides of the resection line, and electrical energy is conveyed from thecoagulation electrode 128 into the tissue as the tissuecoagulation/resection assembly 126 is moved along the resection line. Inthis case, the coagulation electrode 128 may be operated in a monopolarmode.

Referring to FIGS. 17 and 18, an embodiment of a tissuecoagulation/resection assembly 146 constructed in accordance with yetanother embodiment of the present inventions is described. Thecoagulation/resection assembly 146 generally comprises a coagulationelectrode 148 and a tissue resection electrode 150.

The coagulation electrode 148 is composed of a hydrophilic material,which, as previously discussed, is configured for absorbing anelectrically conductive fluid, and may be composed of any one of avariety of materials, such as foam. In the illustrated embodiment, thecoagulation electrode 148 has a tapered circular cross-sectional shape.The coagulation electrode 148 has a lateral surface 152 that can beplaced in contact with tissue to effect a tissue coagulation function.The coagulation electrode 148 may be coupled to the syringe 16 via theperfusion port 30 extending through the probe shaft 18 (shown in FIG.1).

The tissue resection electrode 150 is composed of a biocompatible andelectrically conductive and material, such as stainless steel, gold,platinum, or alloys thereof. The resection electrode 150 has a distaltapered electrode tip 154 having a leading surface 156 that can beplaced in contact with tissue to effect a tissue resection function. Thetissue resection electrode 150 is laterally rigid, i.e., has a shearstrength, so that it resists bending when placed in firm contact withtissue. The resection electrode 150 further comprises an annular recess158 in which the coagulation electrode 148 is suitably mounted, e.g.,via bonding. In this regard, the coagulation electrode 148 is locatedaxially proximal to the tapered electrode tip 154. The lateral surface152 of the tapered coagulation electrode 148 is flush with the leadingsurface 156 of the tapered electrode tip 154. As illustrated in FIG. 18,the coagulation electrode 148 may be placed in fluid communication withthe fluid conduit 28 via a lumen 160 extending through the tissueresection electrode 150 and lateral ports 162.

In the illustrated embodiment, the coagulation electrode 148 andresection electrode 150 are in contact with each other and are operatedin a monopolar arrangement. In this regard, one or both of thecoagulation electrode 148 and resection electrode 150 can be coupled tothe electrical connector 32 via the probe shaft 18 (shown in FIG. 1) orwires (not shown). Alternatively, the surface of the resection electrode150 that would otherwise come in contact with the coagulation electrode148 (in this case, the annular recess 158) can be electrically insulatedtherefrom, so that the coagulation electrode 148 and resection electrode150 can be placed within a bipolar arrangement. Alternatively, theresection electrode 150 can be replaced with a blunt resection memberthat generally takes the same form and shape as the illustratedresection electrode 150, but is not configured to transmit or receiveelectrical energy.

One method of using tissue coagulation/resection assembly 146 will nowbe described in performing a tissue resection. The method comprisesabsorbing an electrically conductive fluid into the coagulationelectrode 148, e.g., by perfusing the coagulation electrode 148 with theelectrically conductive fluid via the perfusion port 30 (shown inFIG. 1) and/or dipping the coagulation electrode 148 into theelectrically conductive fluid. The leading surface 156 of the taperedelectrode tip 154 is placed in contact with the tissue on the resectionline, and the lateral surface 152 of the coagulation electrode 148 isplaced in contact with the tissue on opposite lateral sides of theresection line, and electrical energy (shown by arrows) is conveyed fromthe electrode tip 154 and coagulation electrode 148 into the tissue asthe tissue coagulation/resection assembly 146 is moved along theresection line, thereby coagulating tissue along the resection line andcutting the coagulated tissue, as illustrated in FIG. 19. In theoptional embodiment where the coagulation electrode 148 and resectionelectrode 150 are in a bipolar relationship, the electrical energy(shown by arrows) is conveyed from the coagulation electrode 148 to theresection electrode 150, thereby coagulating tissue along the resectionline and cutting the coagulated tissue, as illustrated in FIG. 20. Ineither mode, the axial relationship between the electrode tip 154 andthe coagulation electrode 148 allows tissue coagulation and cutting tobe accomplished during a single movement along the resection line.Tissue coagulation and separation can be repeated until the tissue iscompletely resected.

Referring to FIG. 21, an embodiment of a tissue coagulation/resectionassembly 166 constructed in accordance with yet another embodiment ofthe present inventions is described. The coagulation/resection assembly166 generally comprises a blunt tissue dissection member 168 suitablymounted to the distal end of the probe shaft 18 (shown in FIG. 1), and apair of tissue coagulation electrodes 170 mounted to the dissectionmember 168.

The dissection member 168 can be composed of any suitable rigidmaterial, but in the illustrated embodiment, is composed of anelectrically insulative material, such as polyether ether ketone (PEEK),polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyamide,polyamide-imide (PAI), polybutadiene, polycarbonate (PC), orpolypropylene (PP), to maintain electrical isolation between thecoagulation electrodes 170, as will be described in further detailbelow. In the illustrated embodiment, the dissection member 168 iscomposed of a unibody structure, although in alternative embodiments,the dissection member 168 may comprise distinct pieces. Any suitableprocess, such as injection molding, can be used to form the dissectionmember 168.

The dissection member 168 has a hook-shaped profile, and in particular,includes a pair of opposing rigid member portions 172 that form achannel 174 therebetween where anatomical vessels, such as bloodvessels, can be captured, and a distal curved member portion 176 fromwhich the opposing member portions 172 proximal extend. The dissectionmember 168 has a pair of opposing, flat, inward facing surfaces 178(only one shown), a pair of opposing, flat, lateral surfaces 180, and aflat, outward facing surface 182.

The coagulation electrodes 170 are composed of a hydrophilic material,which, as previously discussed, is configured for absorbing anelectrically conductive fluid, and may be composed of any one of avariety of materials, such as foam. The coagulation electrodes 170 maybe coupled to the syringe 16 via the perfusion port 30 extending throughthe probe shaft 18 (shown in FIG. 1). A plurality of ports (not shown)may be provided within the lateral surfaces 180 of the rigid memberportions 172 to facilitate distribution of the electrically conductivefluid within the coagulation electrodes 170 via the dissection member168. The coagulation electrodes 170 may be coupled to the electricalconnector 32 via the probe shaft 18 (shown in FIG. 1) or wires (notshown). Although electrical energy may be delivered to the coagulationelectrodes 170 in a monopolar configuration, in the illustratedembodiment, electrical energy is delivered between the coagulationelectrodes 170 in a bipolar configuration to facilitate tissueresection.

To this end, the coagulation electrodes 170 are configured for beingsimultaneously placed in contact with an anatomical vessel, and thecoagulation electrodes 170 are configured for being simultaneouslyplaced in contact with tissue to be resected.

In particular, the dissection member 168 is interposed between thecoagulation electrodes 170, such that the coagulation electrodes 170 arelaterally disposed relative to the dissection member 168. Thecoagulation electrodes 170 are suitably mounted, e.g., via bonding, tothe lateral surfaces 180 of the dissection member 168. In this manner,the coagulation electrodes 170 are configured for contacting the openregions of an anatomical vessel laterally opposite the region of theanatomical vessel closed within the channel 174, with each coagulationelectrode 170 having a pair of inward facing leading surfaces 184 (onlyone shown) configured for contacting opposite sides (i.e., top andbottom) of the anatomical vessel, as illustrated in FIG. 22. Eachcoagulation electrode 170 also has a pair of outward facing leadingsurfaces 186 (only one shown) configured for contacting a surface oftissue to be resected laterally opposite of the dissection member 168.In the illustrated embodiment, the inward facing surfaces 184 andoutward facing surfaces 186 of the coagulation electrodes 170 are flushwith the respective inward facing surfaces 178 and outward facingsurfaces 182 of the dissection member 168, although they may be offsettherefrom a small amount as long as the coagulation electrodes 170 cansimultaneously contact the anatomical vessel to be ligated or the tissueto be resected.

One method of using tissue coagulation/resection assembly 166 will nowbe described in performing a tissue resection. The method comprisesabsorbing an electrically conductive fluid into the coagulationelectrodes 170, e.g., by perfusing the coagulation electrodes 170 withthe electrically conductive fluid via the perfusion port 30 (shown inFIG. 1) and/or dipping the coagulation electrodes 170 into theelectrically conductive fluid. The outward facing surface 182 adjacentone of the resection member portions 172 and/or curved member portion176 is placed in contact with the tissue on the resection line, and theoutward facing surfaces 186 of the coagulation electrodes 170 are placedin contact with the tissue on opposite lateral sides of the resectionline. Electrical energy is then conveyed between the coagulationelectrodes 170 as the tissue coagulation/resection assembly 166 is movedalong the tissue resection line. In this manner, tissue adjacent theresection line is coagulated by the coagulation electrodes 170, whilethe tissue along the resection line is separated by the resection member168. In particular, as illustrated in FIG. 23A, electrical energy (shownby arrows) is conveyed between the respective coagulation electrodes 170through the tissue adjacent the resection line. As a result, theelectrical energy at the interface between the tissue surface and theoutward facing surfaces 182 of the coagulation electrodes 170 coagulatesa band of tissue along the resection line, and the mechanical pressureat the interface between the tissue surface and the resection member 168separates the coagulated band of tissue along the resection line, asillustrated in FIG. 23B.

Alternatively, if the coagulation electrodes 170 are in a monopolarconfiguration, electrical energy can be conveyed to or from one of thecoagulation electrodes 170, while a different portion of thatcoagulation electrode 170, e.g., a lateral surface of the coagulationelectrode 170, is placed on opposite lateral sides of the resection lineto coagulate the adjacent tissue. The dissection member 168 can then beused to separate the coagulated tissue along the resection line.

When an anatomical vessel, such as a blood vessel, is encountered, theanatomical vessel can be slid within the channel 174 between the inwardfacing surfaces 178 of the dissection member 168. Electrical energy isthen conveyed between the coagulation electrodes 170 to seal theanatomical vessel. In particular, as illustrated in FIG. 23C, electricalenergy (shown by arrows) is conveyed from the respective coagulationelectrodes 170 through the vessel tissue. As a result, the electricalenergy at the interface between the top side of the vessel and theportions of the coagulation electrodes 170 adjacent one of the memberportions 172, and the electrical energy at the interface between thebottom side of the vessel and the portions of the coagulation electrodes170 adjacent the other of the member portions 172 causes the top andbottom sides of the closed vessel region to seal.

Although particular embodiments of the present invention have been shownand described, it should be understood that the above discussion is notintended to limit the present invention to these embodiments. It will beobvious to those skilled in the art that various changes andmodifications may be made without departing from the spirit and scope ofthe present invention. Thus, the present invention is intended to coveralternatives, modifications, and equivalents that may fall within thespirit and scope of the present invention as defined by the claims.

1-153. (canceled)
 154. An electrosurgical probe, comprising: anelongated probe shaft; a pair of rigid opposing members distallyextending from the probe shaft, the rigid members having respectiveinward facing surfaces that form a channel therebetween, at least one ofthe inward facing surfaces having a taper, whereby a region of ananatomical vessel that proximally slides within the channel is graduallyclosed by the respective inward facing surfaces; a first vessel ligationelectrode adjacent the inward facing surface of one of the rigidmembers, wherein the first ligation electrode is configured forcontacting a first side of the anatomical vessel at the closed region;and a first hydrophilic electrode laterally disposed relative to the onerigid member, wherein the hydrophilic electrode is configured forcontacting the first side of the anatomical vessel when disposed withinthe channel.
 155. The electrosurgical probe of claim 154, wherein thefirst hydrophilic electrode is composed of an electrically insulativematerial configured for absorbing an electrically conductive solutionthat provides an electrically conductive path through the firsthydrophilic electrode.
 156. The electrosurgical probe of claim 154,wherein the first hydrophilic electrode is configured for absorbing anamount of the electrically conductive solution equal to at least the dryweight of the first hydrophilic electrode.
 157. The electrosurgicalprobe of claim 154, wherein the first hydrophilic electrode is composedof foam.
 158. The electrosurgical probe of claim 154, wherein the onerigid member is composed of an electrically insulative material. 159.The electrosurgical probe of claim 158, wherein the one rigid member hasa recess, and the first ligation electrode is seated within the recess.160. The electrosurgical probe of claim 154, wherein the firsthydrophilic electrode is configured for contacting the first side theanatomical vessel at an open region of the anatomical vessel.
 161. Theelectrosurgical probe of claim 154, wherein both inward facing surfacesof the rigid members taper.
 162. The electrosurgical probe of claim 154,further comprising a second vessel ligation electrode adjacent theinward facing surface of another of the rigid members, wherein thesecond ligation electrode is configured for contacting a second side ofthe anatomical vessel at the closed region opposite the first side ofthe anatomical vessel.
 163. The electrosurgical probe of claim 162,wherein the first hydrophilic electrode is laterally disposed relativeto the other rigid member, wherein the first hydrophilic electrode isconfigured for contacting the second side of the anatomical vessel whendisposed within the channel.
 164. The electrosurgical probe of claim154, further comprising a second hydrophilic electrode laterallydisposed relative to the one rigid member, wherein the one rigid memberis interposed between the first and second hydrophilic electrodes, andwherein the hydrophilic electrode is configured for contacting the firstside of the anatomical vessel when disposed within the channel.
 165. Theelectrosurgical probe of claim 154, wherein the rigid members haverespective outward facing surfaces, the electrosurgical probe furthercomprising a first tissue resection member adjacent the outward facingsurface of one of the rigid members.
 166. The electrosurgical probe ofclaim 165, wherein the first tissue resection member is a tissueresection electrode.
 167. The electrosurgical probe of claim 166,wherein the tissue resection electrode and the first ligation electrodeare formed by the same member.
 168. The electrosurgical probe of claim165, further comprising a second tissue resection member adjacent theoutward facing surface of another of the rigid members.
 169. Theelectrosurgical probe of claim 154, wherein the rigid members are fixedrelative to each other.
 170. The electrosurgical probe of claim 154,further comprising a fluid delivery conduit extending through the probeshaft in fluid communication with the hydrophilic electrode.
 171. Anelectrosurgical probe, comprising: an elongated probe shaft; a pair ofrigid, electrically insulative, opposing members distally extending fromthe probe shaft, the rigid members having respective inward facingsurfaces that form a channel therebetween, at least one of the inwardfacing surfaces having a taper, whereby the channel gradually narrows inthe proximal direction, each of the rigid members having opposinglateral surfaces; a metallic material disposed on the inward facingsurfaces of the rigid members; a hydrophilic material disposed on theopposing lateral surfaces of each rigid member; and at least oneconnector terminal electrically coupled to the metallic material andhydrophilic material.
 172. The electrosurgical probe of claim 171,wherein the hydrophilic material is composed of an electricallyinsulative material configured for absorbing an electrically conductivesolution that provides an electrically conductive path through thehydrophilic material.
 173. The electrosurgical probe of claim 171,wherein the hydrophilic material is configured for absorbing an amountof the electrically conductive solution equal to at least the dry weightof the hydrophilic material.
 174. The electrosurgical probe of claim171, wherein the hydrophilic material comprises foam.
 175. Theelectrosurgical probe of claim 171, wherein the rigid members haverecesses, and wherein the metallic material forms one or more membersseated within the respective recesses.
 176. The electrosurgical probe ofclaim 171, wherein both inward facing surfaces of the rigid memberstaper.
 177. The electrosurgical probe of claim 171, wherein the rigidmembers have respective outward facing surfaces, the electrosurgicalprobe further comprising a pair of tissue resection members adjacent therespective outward facing surfaces of the rigid members.
 178. Anelectrosurgical probe, comprising: an elongated probe shaft; a rigid,electrically insulative, tissue dissection member extending from theprobe shaft, the dissection member having a pair of member portionshaving opposing inward facing surfaces that form a channel therebetween,whereby an anatomical vessel can be captured between the respectiveinward facing surfaces, and opposing lateral surfaces; a hydrophilicmaterial disposed on the opposing lateral surfaces of each of the rigidmembers; and at least one connector terminal electrically coupled to thehydrophilic.
 179. The electrosurgical probe of claim 178, wherein thehydrophilic material is composed of an electrically insulative materialconfigured for absorbing an electrically conductive solution thatprovides an electrically conductive path through the hydrophilicmaterial.
 180. The electrosurgical probe of claim 178, wherein thehydrophilic material is configured for absorbing an amount of theelectrically conductive solution equal to at least the dry weight of thehydrophilic material.
 181. The electrosurgical probe of claim 178,wherein the hydrophilic material comprises foam.
 182. Theelectrosurgical probe of claim 178, further comprising a fluid deliveryconduit extending through the probe shaft in fluid communication withthe hydrophilic material.